Active Nematic Obstacle Courses*

Active fluids, which spontaneously flow under their own internal energy, are commonly composed of nematic constituents, such as filamentous microtubules or rod-like bacteria. The activity and nematic elasticity generate a characteristic lengthscale that competes with any confining lengthscales. This competition of active length and confinement can lead to spatiotemporal ordered flow states, including vortex lattices and double helices in simple confining channels. Building upon recent work in confined active fluids, we employ a hybrid lattice Boltzmann and finite differences numerical solver to simulate an active nematic spontaneously flowing through an obstacle-laden channel. This geometry allows for an investigation of active nematic behaviour in heterogeneous environments. This talk will present our recent findings in channels with different obstacle configurations and imposed boundary conditions. We quantify the role that obstacle configuration can play in either stabilizing ordered flow states or aiding in the transition to disorderly active turbulence. Our numerical work will contribute to constructing a fundamental understanding of the relationship between biological active matter, such as bacterial colonies, and their complex surrounding environments